POS0964 RELATIONSHIP BETWEEN PM2.5 PARTICLE FROM HOUSEHOLD AIR POLLUTION AND INFLAMMATORY AND EPIGENETIC MARKERS IN RHEUMATIC PATIENTS FROM AN INDIGENOUS COMMUNITY IN CHIAPAS: BASELINE STUDY
Authors: J. L. Montiel Hernández, I. Peláez-Ballestas, J. A. Alegria-Torres, C. A. Celia, D. L. Gomez-Galicia, M. A. Garza Elizondo, A. Gastelum-Strozzi
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Chronic exposure to household air pollution (HAP) from cooking by biomass leads to noncommunicable diseases as chronic obstructive pulmonary disease or lung cancer (1), but it is less well known if it could promote epigenetic or proteomic changes leading to autoimmune susceptibility. HAP remains a serious health problem for poor and marginalized indigenous communities. Recent studies have shown a high prevalence of rheumatic disease in Latino American indigenous people (2), but it is unknown if HAP and the PM2.5 particles, could be a risk factor for the pathogenesis of rheumatic diseases. <h3>Objectives</h3> To evaluate the relationship between the levels of PM2.5 derived from HAP and levels of inflammatory and epigenetic markers in rheumatic patients from an indigenous community in Chiapas, México. <h3>Methods</h3> Cross-sectional study nested in a cohort of patients with rheumatic disease in a Tzotzil indigenous community in Chiapas (Southern Mexico). Following the COPCORD methodology and employing an instrument adapted and translated into the local language, people with chronic pain were identified from the adult inhabitants of the community. Rheumatic disease diagnosis was made by a certified rheumatologist. Baseline blood samples were collected from rheumatic patients and controls without rheumatic disease. PM2.5 particle (µg/m<sup>3</sup>) were measured in house indoor air continuously for 37 hours and the mean and accumulated levels calculated. Blood levels of cytokines IL-6, IL-8 and MCP-1 and epigenetic markers (H3K18ac and 5-methylcitosine%) were determined by ELISA. Comparisons between groups were analyzed using the Mann-Whitney U tests. Spearman correlation testing was employed to correlate PM2.5 particle and baseline markers levels. Statistical significance was set at 0.05%. <h3>Results</h3> The indigenous community is made up of 123 adults who live in 53 houses, with an average age of 38.3±16.2 years, where 61.2% are women and 43% only speak local language. Of a total of adult inhabitants, 69 people with chronic pain and 14 patients with different rheumatic diseases (11.4%) were identified. Additionally, 25 biological samples were collected from volunteers without rheumatic disease. When comparing the inflammatory levels and epigenetic markers in the baseline blood samples between these two groups, no significant differences were found. The mean PM2.5 particle inside the houses was 114.5±140.1 µg/m<sup>3</sup> (8.23-462.9), while for control measurements outside it was 9.1±5.5 µg/m<sup>3</sup> (4-14.9). However, when comparing PM2.5 levels at homes of patients and controls, no significant differences were found (40.99 vs. 65.19 µg/m<sup>3</sup>). Likewise, no significant correlation was observed between inflammatory markers or epigenetic markers, either when evaluating as group or as a whole. It is necessary to complete the baseline study by evaluating citrullination levels in sputum and blood samples, as well as perform a deeper analysis of exposure time to high levels of the PM2.5 particle. <h3>Conclusion</h3> We found no relationship between PM2.5 levels and the levels of inflammatory or epigenetic markers, suggesting that HAP could have a more complex pathogenesis than expected on rheumatic health. <h3>References</h3> [1]Chen KC. et al. 2022. Indoor Air Pollution Increases the Risk of Lung Cancer. Int J Environ Res Public Health 19. [2]Pelaez-Ballestas, I. et al. 2018. Epidemiology and socioeconomic impact of the rheumatic diseases on indigenous people: an invisible syndemic public health problem. Ann Rheum Dis. 77: 1397-1404. <h3>Acknowledgements</h3> This work was supported by a grant from CONACYT CF-2019 (#2000052). <h3>Disclosure of Interests</h3> None Declared.